Technical Field
The present disclosure relates generally to a surgical stapling device for applying surgical staples to body tissue. More particularly, the present disclosure relates to a surgical stapling device suitable for performing curved or circular anastomosis and/or treatment to internal tissue and/or to internal walls of hollow tissue organs.
Background of Related Art
Anastomosis is the surgical joining of separate hollow organ sections. Typically, an anastomosis procedure follows surgery in which a diseased or defective section of hollow tissue is removed and the remaining end sections are to be joined. Depending on the desired anastomosis procedure, the end sections may be joined by either circular, end-to-end or side-to-side organ reconstruction methods.
In a circular anastomosis procedure, the two ends of the organ sections are joined by means of a stapling instrument which drives a circular array of staples through the end section of each organ section and simultaneously cores any tissue interior of the driven circular array of staples to free the tubular passage. Examples of instruments for performing circular anastomosis of hollow organs are described in U.S. Pat. Nos. 6,053,390, 5,588,579, 5,119,983, 5,005,749, 4,646,745, 4,576,167, and 4,473,077, each of which is incorporated herein in its entirety by reference. Typically, these instruments include an elongated shaft having a handle portion at a proximal end to actuate the instrument and a staple holding component disposed at a distal end. An anvil assembly including an anvil rod with attached anvil head is mounted to the distal end of the instrument adjacent the staple holding component. Opposed end portions of tissue of the hollow organ(s) to be stapled are clamped between the anvil head and the staple holding component. The clamped tissue is stapled by driving one or more staples from the staple holding component so that the ends of the staples pass through the tissue and are deformed by the anvil head. The staples are driven from the staple holding component by a pusher or pushers. An annular knife is concurrently advanced to core tissue with the hollow organ to free a tubular passage within the organ.
Besides anastomosis of hollow organs, surgical stapling devices for performing circular anastomosis have been used to treat internal hemorrhoids in the rectum. Typically, during use of a circular stapling device for hemorrhoid treatment, the anvil head and the staple holding component of the surgical stapling device are inserted through the anus and into the rectum with the anvil head and the staple holding component in an open or unapproximated position. Thereafter, a purse-string suture is used to pull the internal hemorrhoidal tissue towards the anvil rod. Next, the anvil head and the staple holding component are approximated to clamp the hemorrhoid tissue between the anvil head and the staple holding component. The stapling device is fired to remove the hemorrhoidal tissue and staple the cut tissue. A surgical stapler for treating hemorrhoids is disclosed in Heinrich, U.S. Pat. No. 6,959,851, the disclosure of which is hereby incorporated by reference herein.
In circular stapling devices, typically a gap or spacing between adjacent staple forming pockets and corresponding staple retaining pockets, in each annular row, is greater for a radially outward row as compared to a radially inward row. The staples have a straight backspan and the staple forming pockets and staple retaining pockets have a straight longitudinal axis. The inner annular row of staple forming pockets and/or staple retaining pockets determines the number of staples for each annular row. Each annular row has the same or equal number of staple forming pockets and/or staple retaining pockets. Accordingly, the gap between adjacent staple forming pockets and/or staple retaining pockets, in each annular row is greatest in the outer annular row as compared to the inner annular row.
Accordingly, a need exists for providing a circular surgical stapling device wherein the gap between adjacent staple forming pockets and/or staple retaining pockets, in each annular row is reduced or maintained in each annular row thereof, from the outer annular row to internal tissue and/or to the inner annular row.